2021-10-27 21:31:06

by Valentin Schneider

[permalink] [raw]
Subject: [PATCH v2 0/3] irqchip/gic-v3-its: Fix LPI pending table handling vs PREEMPT_RT

Hi folks,

This is my take at fixing [1]. Reading about the LPI tables situation was
entertaining.

Tested against kexec on an Ampere eMAG. Seems to be working fine atop
5.15-rc6. On the other hand, I can only issue one kexec from
5.15-rc6-rt12 - if I then issue another one on the new kernel, I get tasks
hanging. That is true even without my patches and without
CONFIG_PREEMPT_RT.

[1]: http://lore.kernel.org/r/[email protected]

Revisions
=========

v1 -> v2
++++++++

o Ditched RDIST_FLAGS renaming; moved to "RD_LOCAL" prefix for new flags
(Marc)
o Simplified cpuhp callback logic: body now runs at most once per CPU
o Changed cpuhp callback installation to happen *after* the BP has invoked
its_cpu_init(); the BP cpuhp state is immediately set to CPUHP_ONLINE, so
cpuhp state alone doesn't guarantee its_cpu_init() has been run.

Cheers,
Valentin

Valentin Schneider (3):
irqchip/gic-v3-its: Give the percpu rdist struct its own flags field
irqchip/gic-v3-its: Postpone LPI pending table freeing and memreserve
irqchip/gic-v3-its: Limit memreserve cpuhp state lifetime

drivers/irqchip/irq-gic-v3-its.c | 82 +++++++++++++++++++++++++++---
drivers/irqchip/irq-gic-v3.c | 1 +
include/linux/irqchip/arm-gic-v3.h | 4 +-
3 files changed, 79 insertions(+), 8 deletions(-)

--
2.25.1


Subject: Re: [PATCH v2 0/3] irqchip/gic-v3-its: Fix LPI pending table handling vs PREEMPT_RT

On 2021-10-27 16:15:03 [+0100], Valentin Schneider wrote:
> Hi folks,
Hi,

> This is my take at fixing [1]. Reading about the LPI tables situation was
> entertaining.
>
> Tested against kexec on an Ampere eMAG. Seems to be working fine atop
> 5.15-rc6. On the other hand, I can only issue one kexec from
> 5.15-rc6-rt12 - if I then issue another one on the new kernel, I get tasks
> hanging. That is true even without my patches and without
> CONFIG_PREEMPT_RT.

What is the status of this? I haven't seen any replies, is this just
sitting to be merged?

Sebastian

2021-11-19 12:28:41

by Marc Zyngier

[permalink] [raw]
Subject: Re: [PATCH v2 0/3] irqchip/gic-v3-its: Fix LPI pending table handling vs PREEMPT_RT

On Fri, 19 Nov 2021 11:14:53 +0000,
Sebastian Andrzej Siewior <[email protected]> wrote:
>
> On 2021-10-27 16:15:03 [+0100], Valentin Schneider wrote:
> > Hi folks,
> Hi,
>
> > This is my take at fixing [1]. Reading about the LPI tables situation was
> > entertaining.
> >
> > Tested against kexec on an Ampere eMAG. Seems to be working fine atop
> > 5.15-rc6. On the other hand, I can only issue one kexec from
> > 5.15-rc6-rt12 - if I then issue another one on the new kernel, I get tasks
> > hanging. That is true even without my patches and without
> > CONFIG_PREEMPT_RT.
>
> What is the status of this? I haven't seen any replies, is this just
> sitting to be merged?

No. This is in my review queue, and I'm massively behind. Nobody else
seems to risk reviewing GIC stuff (no idea why...).

M.

--
Without deviation from the norm, progress is not possible.